When printing the printer is leaving smears on the left side of the page and random letters. If I make 20 copies, the first 5 and the last few will have the marks. I already changed the drum and all cartridges.

Select the simplex/duplex mode.
1 sided - 1 sided
1 sided - 2 sided
2 sided - 2 sided
When using 1 sided to 2 sided the originals must be even

Here are "little" specification:

Body installation method desktop page printer
Photosensitive medium OPC drum
Exposure method semiconductor laser
Development method Toner projection development
Transfer method by roller
Separation method by curvature
Cassette pickup method by pad
Multifeeder pickup method by pad
Drum cleaning method by blade
Fixing method on-demand
Delivery method face-down/face-up
Toner supply type by toner cartridge
about 6000 prints (A4, single-sided; at 5% image ratio)
Warm-up time in standby: 0 sec (at power-on: 10 sec or less)
Print area top: 5 mm; bottom: 5 mm; left/right: 5 mm (if envelope, top, bottom, left,
right: 10 mm)
Printing resolution 600dpi
First print time 9 sec or less (approx.; A4)
Print speed (A4) 21 pages/min (approx.)
Cassette paper size A4, B5, A5, Legal, Letter, Executive
Multi-purpose paper size A4, B5, A5, Legal, Letter, Executive, Envelope DL, Envelope COM10,
Envelope C5, Envelope Monarch, Index Card, Custom Paper Size (width
76.2 to 215.9 mm, length 127.0 to 355.6 mm)
Cassette paper type plain paper (64 to 90 g/m2), heavy paper (91 to 120 g/m2), recycled
Multi-purpose paper type plain paper (64 to 90 g/m2), heavy paper (91 to 163 g/m2), recycled
paper, transparency, label paper, envelop (DL, COM10, C5, Monarch,
B5)
Cassette capacity 250 sheets (approx.; plain paper, 64 g/m2)
Multi-purpose capacity 1 sheet
Delivery tray stack 65sheets (Face-down) /1sheet(Face-up Output Slot)
Memory 8 MB (internal; no optional memory available)
Operating environment
(Temperature range) 10 to 32.5 deg C
Operating environment
(Humidity range) 20% to 80% RH
Noise 52.8 dB or less (during printing; based on ISO9296; announced noise
emission)
Power supply rating AC100V±10% (50/60Hz ±2Hz)
Power consumption (Maximum) 790W or less (approx.; 20 deg C; for input of rated power supply;
including peak value lasting 1 sec or more)
Dimensions 370 (W) x 375 (D) x 258 (H)mm
Weight printer: Approx;11kg; toner cartridge: Approx,0.8kg(2.5K)
Option paper feeder

Smeared output can also result when you refeed a printed page into the printer to make a double-sided page. This happens because the rubber rollers that grip the paper to pull it into the printer can pick up toner from the first side’s printing and smear it. So before replacing this is an easy thing to check. Printing multiple pages consecutively will make the pages print progressively cleaner.

Smeared toner also happens because the nonstick coating on the fusing roller is scratched or has baked-on debris. This can happen if the printer is in a dirty environment especially. If you are comfortable removing the fuser, you can try to clean it with a soft cloth and alcohol, but make sure you let it cool down first!

If this does not resolve your issue then make sure the fuser is heating; if not, the thermostat is bad and you will most likely need to replace the entire fuser assembly. This will be pretty expensive to repair so hopefully it's one of those other issues.

Smeared output can result when you refeed a printed page into the printer to make a double-sided page. This happens because the rubber rollers that grip the paper to pull it into the printer can pick up toner from the first side’s printing and smear it. So before replacing parts, this is an easy thing to check. Printing multiple pages consecutively will make the pages print progressively cleaner or you can clean the rollers with rubbing alcohol.

Smeared toner also happens because the nonstick coating on the fusing roller is scratched or has baked-on debris. This can happen if the printer is in a dirty environment especially. If you are comfortable removing the fuser, you can try to clean it with a soft cloth and alcohol, but make sure you let it cool down first!

Finally, if this does not resolve your issue then make sure the fuser is heating; toner that is not heated properly will fall from the page and smear. If the thermostat is bad or the fuser not working properly, you will most likely need to replace the entire fuser assembly. This will be pretty expensive to repair so hopefully it's one of those other issues.

Please check the printer ink levels and if the ink level is fine and it still not printing then I will like to know type printer you are using,then I can carring on from there.

This sounds like a corrupt print driver. Try uninstalling and reinstalling the driver.

You need to clean the print head until the smears clear up

Are you able to copy without any problem.
If not try the link bellow:

http://h10025.www1.hp.com/ewfrf/wc/document?lc=en&cc=us&docname=c00806164&dlc=en&product=1141647

Good Luck

Sounds as though one of the drum cleaning blades is failing.

When you see the double image shadow, is it any particular color? If so, that's the drum unit that is failing.

Make sure that manual feed is set to letter, on the printer front panel. This is a tabloid printer, so letter size sheets are fed long edge. The cassette will print okay because the media size info for the cassette is read by the printer from the cassette cams.